1. Field of the Invention
This invention relates to a control apparatus of an internal combustion engine operable on fuels of different octane numbers.
2. Description of the Prior Art
In recent years, high-octane unleaded gasoline (octance number=98) has become available in addition to conventional low-octane unleaded gasoline (octane number=91). Under such circumstances, various types of engines that can operate on fuels of different octane numbers have been proposed.